工程测量1（Engineering Survey 1）.docVIP

工程测量1（Engineering Survey 1） Preparation before building construction survey: 1 Preparation: understanding the relationship between the building and the known building; the size of the construction building 2 site visit: terrain, topography, surveying control network etc. 3. Determine the design plan: design methods, instruments, accuracy requirements, timing 4. Check the survey data The difference between high speed rail and traditional railway: 1. High speed railway assembly line engineering survey and track system construction survey are carried out under different coordinate standards 2. High speed railway control survey line, engineering survey control network and track control network 3. High precision required 4 、 high-precision GNSS receiver / intelligent total station / digital level and track detector and other precision measuring instruments are widely used in high-speed railway construction Characteristics of construction control network: 1 、 high precision, small control range and large density of control points 2, according to the size of the project, can be divided into two stages or multistage network, the secondary network precision possible than the head high 3. Control points are frequently used and subject to construction interference. Regular retest is required 4. In order to coordinate calculation and construction lofting, the coordinate system of control network is in accordance with the construction coordinate system 5. In order not to make the projection correction and easy to set out, the projection surface is consistent with the average elevation surface Slope line survey: Method: in AB into two inclined stakes, if A point elevation is known, in the A point placement level, with the general method of measuring B elevation in AB between 1 and 2, 3, 4, a foot screw in the direction of AB, the other two foot spiral line roughly the AB line and vertical measuring instrument of high I, with a telescope aimed at the level of B points feet, foot s